Metric system of measurement
Topic: Maps and Map Scale · NCERT: Class 11, Ch 2 "Map Scale"
Meaning
The metric system measures length in kilometres, metres and centimetres. Its units go up in tens, so it is easy to convert: 1 km = 1,000 m = 100,000 cm. India has used it since 1957, and so do most countries. It makes it easy to read a representative fraction (RF), because you just knock off zeros to turn centimetres into metres or kilometres.
Example
On a 1:50,000 Survey of India toposheet, 1 cm on the map equals 50,000 cm on the ground. That is 500 m. On a 1:100,000 map, 1 cm equals 100,000 cm, which is exactly 1 km.
Don't confuse with
- English system of measurement: uses miles, furlongs, yards, feet and inches. Its units are not in tens (1 mile = 63,360 inches). The USA and the UK still use it, and India used it before 1957.
Related concepts
- Map scale
- Statement of scale
- Graphical scale
- Representative fraction
- English system of measurement
- Conversion of scale